I don't have any idea but why don't you freeze it? At -20 it can be stored for ages!

thanks, I have some aliquotes that are already at -20, but the concentration is much higher . Unfortunately I made too big aliquotes, so when I dilute 1 aliquote to the working concentration, that is 100 microg/ml, I don't know if I can just keep in the fridge ( and for how many days?) or refreeze. what do you do usually?

I don't have any idea but why don't you freeze it? At -20 it can be stored for ages!

thanks, I have some aliquotes that are already at -20, but the concentration is much higher . Unfortunately I made too big aliquotes, so when I dilute 1 aliquote to the working concentration, that is 100 microg/ml, I don't know if I can just keep in the fridge ( and for how many days?) or refreeze. what do you do usually?

I made 10 ml of the solution of the right concentration, froze them in a 15 ml tube and defrost it every time I need it to add 50 ul to my samples. Than I freeze it again. So I don't aliquot it at all and it works fine.

I don't have any idea but why don't you freeze it? At -20 it can be stored for ages!

thanks, I have some aliquotes that are already at -20, but the concentration is much higher . Unfortunately I made too big aliquotes, so when I dilute 1 aliquote to the working concentration, that is 100 microg/ml, I don't know if I can just keep in the fridge ( and for how many days?) or refreeze. what do you do usually?

I made 10 ml of the solution of the right concentration, froze them in a 15 ml tube and defrost it every time I need it to add 50 ul to my samples. Than I freeze it again. So I don't aliquot it at all and it works fine.

thanks. I think I will waste this ( that is >1 month that is in the fridge) and make another 100 ug/ml solution and do like you do